1. Field of the Invention
The present invention relates to an optical disk driving device for holding and rotating disk-like recording media such as optical disks (CDs, DVDs etc.) or optical magnetic disks (hereinafter simply referred to as xe2x80x9cdisksxe2x80x9d) and for irradiating light beams for recording or reproducing information.
2. Description of the Background Art
Disks such as CDs or DVDs are being paid attention to as information recording media in recent years, and many such disks are being developed to be of high density and large capacity and are produced all over the world since they may be produced at low costs. There are further being suggested various optical disk driving devices for rotating such disks for the purpose of recording or reproducing information.
A conventional optical disk driving device will now be explained.
FIG. 14 is a schematic view illustrating an arrangement of a conventional optical disk driving device. In FIG. 14, a disk 109 is fixed in a known manner in that its central proximate portion 109a is mounted on a turntable 101 and in that the disk is pinched between the turntable 101 and a clamper 102 that is of substantially identical diameter as that of the turntable 101. Some of the major methods for pinching and fixing the disk between the turntable 101 and the clamper 102 will be explained.
In one possible method, the clamper 102 is arranged at a disk lid of a box-shaped portable device in a freely rotating manner such as in so-called portable CD devices wherein the clamper 102 is moved and pressurized against the turntable 101 by closing the disk lid to fix (or hold) the disk.
In another method, which is mainly used in stationary devices of so-called tray systems, a disk 109 that is moved onto the turntable 101 by a tray is lifted from the tray by the movement of the turntable 101 and is pressurized against a freely rotating clamper 102 to fix the disk 109.
In still another method, of a so-called slot-in system as frequently used in CD players for use in car stereos or the like, a disk that has been inserted into a slot (slot of narrow width) by a user in a known manner is moved onto the turntable 101 by a rubber-like roller or similar means and the disk 109 is pinched and held by the movement of the turntable 101 or a freely rotating clamper 102.
As well known, a tapered portion (not shown) is provided on a surface of the turntable 101 on which the disk is mounted as a means for centering the disk so that inner peripheral end portions of the disk 109 may be pinched and held in the centered position.
Major means for pinching and holding are those employing magnetic force of a magnet. A magnet is mounted to either of the clamper or the turntable and the other member is mounted with sheet metal. Fixing is achieved through a mutually pinching and holding force in the presence of such magnetic force of the magnet. It goes without saying that both members may be comprised of magnets to achieve the same effects. However, since such an arrangement will increase manufacturing costs, it is generally the case that either one is formed with sheet metal.
In the above-described optical disk driving device in which the disk 109 is pinched and held between the turntable 101 and the clamper 102, the disk 109 is rotated simultaneously with the rotation of the turntable 101, and light beam L is irradiated from a pickup 103 that moves in a radial direction of the disk 109 (direction indicated by arrow R in the drawing). By the irradiation of the light beam L, information may be recorded on the disk 109 or information that has been recorded on the disk may be reproduced upon reflection by the disk 109.
In order to perform high-density recording or reproduction of information, it is necessary to accurately irradiate the light beam onto the disk 109 and the reflected light beam needs to be accurately received. It is thus necessary to strictly define focus control of the light beam for achieving focus of the light beam on the surface of the disk (more particularly, on an information surface on an inner surface of the disk) and angles between the disk surface and the light beam.
To cope with this matter, a conventional optical disk driving device is arranged to perform the above-described focus control and to perform so-called tilt control for tilting the pickup 103 for irradiating the light beam in a manner as indicated by the arrow C in the drawing for setting the angle between the disk surface and the light beam to be within a defined value so as to also enable recording and reproduction of warped, flexed or deflected disks as illustrated in the schematic side view of FIG. 15.
It is further generally the case with such a conventional optical disk device that the optical disk is first mounted onto a disk tray (hereinafter simply referred to as xe2x80x9ctrayxe2x80x9d) through operations of a user, whereupon the optical disk is moved together with the tray to be retracted into the interior of the device. At this time, the clamper, which has a substantially identical radius as a radius of the turntable, is supported by a clamp plate that is fixed to bridge over the turntable and is suspended down through its own weight, and the tray had so far been designed to avoid interference with the clamper during its movement.
However, in order to precisely irradiate a light beam onto tracks of the disk and to make the light beam follow the tracks, it is required in the above-described conventional optical disk driving device that the pickup for irradiating light beam be comprised with a mechanism for accurately moving the same in the radial direction of the disk and further with a tilt mechanism for tilting the pickup to follow the warpage of the disk. A drawback was consequently presented in that the mechanism of the conventional optical disk driving device was complicated and downsizing thereof could hardly be achieved. It was another drawback that movements of the tray were hindered by a large clamper when the large clamper for pressurizing an outer peripheral portion of the disk was mounted on the conventional optical disk device.
The present invention has been made in order to solve the above conventional problems, and it is an object thereof to provide an optical disk driving device that is capable of accurately performing recording and reproduction also with warped disks without the provision of a tilt mechanism and that is provided with a moving means for the clamper such that movements of the tray are not hindered.
In order to achieve this object, the disk-like recording medium driving device of the present invention is arranged in that a clamper (or a turntable) for pinching and holding the disk-like recording medium is comprised of a central clamper (or a central turntable portion) for pinching and holding a proximity of an inner edge of the disk-like recording medium with the turntable (or the clamper) and an outer clamper portion (or an outer turntable portion) abutting against an outer periphery of the disk-like recording medium.
With this arrangement, it is possible to obtain a disk-like recording medium driving device that is arranged to abut and pressurize a proximity of an outer periphery of the warped disk at which no information is recorded, to thereby correct the warpage, to restrict an angle between an information recording surface of the disk and the light beam that is irradiated for recording and reproducing information to be within a specified value, and to precisely read information for accurately performing recording and reproduction.
The present invention is directed to an optical disk driving device for pinching and holding an optical disk that is mounted on a rotationally driving turntable with a clamper that is supported in a freely rotating manner, wherein the clamper of the disk-like recording medium driving device is comprised of a central clamper portion for pinching and holding a proximity of an inner edge of the optical disk with the turntable and an outer clamper portion abutting against an outer periphery of the optical disk.
With this arrangement, by abutting and pressurizing a proximity of an outer periphery of a disk, which is warped toward the clamper side, on which no information is recorded, it is possible to exhibit effects of correcting the warpage, of restricting an angle between an information recording surface of the disk and the light beam that is irradiated for recording and reproducing information to be within a specified value, and of precisely reading information for accurately performing recording and reproduction.
The device further comprises a pressurizing unit for pressurizing the clamper against the turntable, a surface deflection amount detecting unit for detecting an amount of surface deflection of the mounted optical disk, and a control unit for sending instructions to the pressurizing unit to increase pressurizing force depending on the detected results of the amount of surface deflection obtained by the surface deflection amount detecting unit.
With this arrangement, in case the amount of surface deflection is larger than a defined value, the pressurizing force is increased by the pressurizing unit to perform correction so that stable reproduction can be achieved even with largely warped disks.
The turntable is preferably comprised of a central turntable portion for pinching and holding a proximity of an inner edge of the disk-like recording medium with the clamper, and an outer turntable portion abutting against an outer periphery of the disk-like recording medium.
With this arrangement, by abutting and pressurizing a periphery of an outer periphery of a disk, which is warped toward the turntable side, at which no information is recorded, it is possible to exhibit the effects of correcting the warpage, of restricting an angle between an information recording surface of the disk and the light beam that is irradiated for recording and reproducing information to be within a specified value, and of precisely reading information for accurately performing recording and reproduction.
The device is particularly characterized in that the turntable is comprised with spokes for supporting the outer turntable portion from the central turntable portion, and it is therefore possible to exhibit the effect of preventing a case in which the light beam for reading optical information on the disk is not at all irradiated onto the disk and that optical information may also be partially read.
The device has particularly been devised to further comprise a pickup for irradiating light beams onto the optical disk, a pickup controlling unit for controlling the pickup, a turntable rotating mechanism for controlling rotation of the turntable and outputting a rotational position signal for indicating a position of rotation, and a control unit for sending instructions to the pickup controlling unit to interrupt focus control of the pickup depending on a rotational phase upon input of the rotational position signal of the turntable, wherein the turntable is comprised with spokes for supporting the outer turntable portion from the central turntable portion.
With this arrangement, it is possible to eliminate influences of interruption of the light beams through the spokes for supporting the outer turntable portion and to perform stable reproduction.
According to another aspect, the present invention relates to an optical disk driving device for pinching and holding an optical disk, which is mounted on a position that is concentric with a turntable fixed to a rotating axis of a spindle motor, with a clamper that is supported in a freely rotating manner, the clamper of the optical disk driving device being comprised of a central clamper for pinching and holding a proximity of an inner edge of the optical disk with the turntable and an outer clamper portion abutting against an outer periphery of the optical disk, wherein the device further comprises a clamper moving mechanism for moving the clamper in a direction opposite to (i.e. away from) an upper surface of the turntable unless the turntable and clamper are in pinching and holding conditions.
With this arrangement, it is possible to provide an optical disk driving device that is capable of accurately performing recording and reproduction even with warped disks without the provision of a tilt mechanism and wherein a moving mechanism for the clamper is provided such that movements of the tray are not hindered.
That is, with this arrangement, the optical disk driving device is capable of exhibiting an action of correcting warpage by abutting and pressurizing a proximity of an outer periphery of a disk-like recording medium (an optical disk) at which no information is recorded, of restricting an angle between an information recording surface of the disk and the light beam that is irradiated for recording and reproducing information to be within a specified value, and of precisely reading information for accurately performing recording and reproduction without the necessity of providing any complicated tilt mechanisms. This optical disk driving device, which is provided with an outer clamper portion, further exhibits the action of moving the outer clamper portion so as not to hinder movements of the tray.
The optical disk driving device may further have the clamper supported at a position that is concentric with the turntable, a spring member having one end abutting the clamper and the other end abutting a spring holder that is mounted at a position concentric with the clamper, a spring hook that pierces through the clamper and that is fixed to the spring holder with the clamper and the spring member being interposed between, and a clamp plate for supporting the spring hook, wherein the spring hook is supported by the clamp plate unless the turntable and the clamper are in pinching and holding conditions and wherein the clamper is moved by the spring member interposed between the clamper and the spring holder.
With this arrangement, the spring hook may be supported by the clamp plate unless the turntable and the clamper are in pinching and holding conditions, and the spring holder that is fixed to the spring hook may be simultaneously supported. It is possible to exhibit an action of having the clamper moved by the spring member that is interposed between the supported spring holder and the clamper.
The optical disk driving device may further be arranged such that the clamper has a first magnet mounted thereon, a clamp plate is disposed on a side of the clamper opposite the turntable, and a second magnet is mounted on the clamp plate, wherein the clamper is moved through mutual pulling owing to magnetic force of the first magnet and the second magnet unless the turntable and the clamper are in pinching and holding conditions.
With this arrangement, it is possible to exhibit an action of moving the clamper through mutual pulling owing to magnetic force of the first magnet and the second magnet unless the turntable and the clamper are in pinching and holding conditions.